When a exposed silver halide color photographic light sensitive material is developed, dyes are produced by coupling between the color developing agent oxidation product resulting from the development of the silver halide and the coupler. The color reproducibility of color printing paper etc. using such a coupling reaction to provide color images depends largely upon the coupler and color developing agent. Known cyan couplers commonly used in silver halide color photographic light sensitive materials such as color printing paper include 2,5-diacylaminophenol-based cyan couplers and phenol-based cyan couplers having both an acylamino group at 2-position and an alkyl group at 5-position.
N,N-di-substituted paraphenylenediamine compounds are widely used as color developing agents. 3-ethyl-4-amino-N-ethyl-N-(.beta.-methanesulfonamidoethyl)-aniline sulfate is a well-known color developing agent for photographic materials containing such a cyan coupler.
However, such a cyan dye obtained by using a cyan coupler and a color developing agent in combination does not permit provision of high chromaticness because of high absorption of blue light and green light due to spectral broadening on the short wave side.
Japanese Patent O.P.I. Publication No. 96656/1988 discloses a method of improving color reproducibility by reducing green light absorbance by increasing the maximum absorption wavelength of formed dye by the use of a sulfonamide compound and a diacylaminophenol-based cyan coupler in combination.
This method permits improvement in cyan tone, but the spectral broadening on the short wave side remains intact to a rather high degree and thus reduces green light absorbance. This drawback has been expected to be overcome.
The method disclosed in Japanese Patent O.P.I. Publication No. 96656/1988 permits lowering of the subabsorption of yellow light at 420 nm comparison with phenol-based cyan couplers having an alkyl group at 5-position, but it is desired that this subabsorption is further lessened to improve color reproducibility.
Such improvement in the spectral absorption characteristic of cyan dye significantly affects the color reproducibility of ordinary color prints. Color photographic materials are also used to prepare color proofs from color-separated black-and-white dot images used in the printing and processing processes. In this case, the spectral absorption characteristic of cyan images plays a key role. Accordingly, in general, the cyan dye for printing ink has a vivid color because its spectral broadening on the short wave side below the maximum absorbance wavelength is small and, in addition, the blue light absorbance is low, while the cyan dye obtained by color development of a coupler has a fault that the produced color looks more clouded than the color of printing ink and/or looks greenish because the blue light and green light absorbance is high.